1. Field of the Invention
This invention relates to a removable locking device to hold and secure the connection between typical nut type end fittings on two fluid transmission lines being detachably joined together.
2. Prior Art
Fluid transmission lines, such as those carrying reactive gases used in certain semiconductor manufacturing processes, are often vulnerable to leaks or breakage induced by stress from vibration, twisting, temperature change or other environmental conditions. This frequently results in significant downtime, costly repairs and loss of production. Standard, detachable nut type fittings such as, but not limited to those supplied by Cajun and Fox, rely principally upon friction and threaded type connection to achieve and maintain tight, leak proof seals which are generally resistant to significant leakage or breakage. Experience has shown that such connections do fail, under continuous use, from vibration, line twisting and temperature change, often enough to affect significantly the above mentioned industrial operations. Experience has also shown that the failure occurs most frequently at the union of the lines, due to loosening of the detachable, nut type connecting fittings.
Review of the patent literature indicates that there are many lock type devices designed to hold a variety of nut type end fittings together. However most of them are of special, often complicated design, requiring customized components not readily adaptable to commercially available, standard detachable nut type fittings.
One relative simple device is described in U.S. Pat. No. 2,880,637, issued Apr. 7, 1959, to Koenig. This invention consists primarily of a readily attachable nut lock for a nut have a circumferential groove thereon or an available unengaged thread at the upper portion of the connecting bolt, said nut lock comprising a wrench having a nut engaging portion and a portion or spline extending outwardly from the axis of the nut and a special, resilient clamp, such as a spring clip, adapted to be slipped on the wrench after it has been torqued, to hold it against longitudinal displacement relative to the nut and a fixed adjacent structure. This method works for one nut but does not obviously lead to development of the device to be described and distinguished herein.